The Bombardier CL-600-2E25 Regional Jet CRJ-900LR is a twin-engine regional jet airliner for
2 crewmembers and up to 90 passengers. Development of the CL-600 Challenger family started in 1974, when Bill
Lear designed the LearStar 600, a 12-place business jet. Canadair bought the manufacturing rights in 1976,
and renamed the design Canadair CL-600 Challenger. The first prototype of the airplane flew on 8 November 1978.
The second and third prototypes flew in March and July 1979. On 3 April 1980, a test flight with
the first prototype above the Mojave Desert ended in a disaster, with the airplane crashing due
to a deep stall. In August 1980, certification was granted with temporary restrictions. Deliveries of
the CL-600, powered by two Lycoming ALF-502L turbofans started in 1981. The design
was developed further and in 1984 Canadair studied about a stretched airliner based
on the CL-600. After Bombardier Aerospace bought Canadair in 1986, design studies for
a stretched airliner version of the Bombardier Challenger family of business jets started
again in 1987. This design study resulted in the Canadair Regional Jet program. The first
of three development aircraft flew on 10 May 1991. The Model CL-600-2B19, CRJ100, the first
and smallest aeroplane in the Bombardier CRJ Series, entered service in 1992. The CL-600-2B19,
the base aircraft for most comparison exercises, employs older system technology when compared to other CRJ variants.
It is marketed in three separate series: the CRJ-100, CRJ-200 and the CRJ-440.The CRJ-200
series of the Canadair Regional Jet is powered by two General Electric CF-34-3B1 engines
and entered production in 1995. Following the success of the CRJ100/200 series, Bombardier produced larger variants:
the Bombardier CRJ700, CRJ900, and CRJ1000. Design work on the CRJ700 by Bombardier started in 1995 and the programme
was officially launched in January 1997. The Model CL-600-2C10 was the first new variant from the original 50-seat aeroplane.
Product improvements included, but were not limited to: a fuselage stretch; FADEC-controlled engines; a new wing with leading
edge slats; a forward under-floor cargo compartment; and upgraded and automated aircraft systems. The aircraft entered service
in 2000 and was marketed as the CRJ 700 (68 seats); CRJ701 (70 seats); and CRJ702 (77 seats). The CL-600-2D24 was the third CRJ
variant. Basically a stretched version of the CL-600-2C10, product improvements included, but were not limited to: a fuselage stretch;
increased thrust output from the engines; additional over-wing exits, and a larger forward under-floor cargo compartment. The environmental
packs have a target temperature instead of a hot-cold knob. The cabin has a recirculation fan which aids in cooling and heating. The engines
are controled by FADEC digital engine control instead of control cables and a fuel control unit. The cabin floor has been lowered 2 inches
which gains outward visibility from the windows in the cabin as the windows become closer to eye level height. The APU is a
Honeywell RE220 unit which supplies much more air to the AC packs and has higher limits for starting and altitude usage.
The wingspan is longer, the tail is redesigned with more span and anhedral. The aircraft entered service in 2002 and was
marketed as the CRJ-900 (up to 90 passengers). The CRJ-900 could be obtained as a standard or extended-range version; the only
difference between the versions is the maximum operating weights. On 19 February 2007, Bombardier officialy started
the development of the CRJ1000, previously designated CRJ900X, as a stretched CRJ900, with up to 100 seats. On 28 July 2009,
the CRJ1000 completed its first production flight and first deliveries were planned then for the first quarter of 2010.
A month after the first flight, however, a fault in the rudder controls forced the flight-test program to be grounded.
The program was not resumed until February 2010, and deliveries were postponed to 14 December 2010 with Brit Air and Air Nostrum
as the launch customers for the CRJ1000. The FAA Type Certificate designation of the CRJ1000 is the CL-600-2E25.

The 2011-built Bombardier CL-600-2D24 Reginal Jet CRJ-900LR c/n 15263 was flown first with as D-ACNR. On 25 February 2011,
the aircraft was handed over to Eurowings and flown to Düsseldorf in Germany, where it arrived on 26 February 2011.
Bombardier CRJ-900LR D-ACNR was operated by Eurowings for Lufthansa Regional. In the period 30 March 2014 - 24 October 2015,
Eurowings operated the D-ACNR for Germanwings. On 21 October 2016, Bombardier CRJ-900LR D-ACNR was transferred to Lufthanse
CityLine and as before the aircraft was operated for Lufthansa Regional. On 27 September 2017, Bombardier CRJ-900LR NextGen
D-ACNR "Ratingen" was seen on Taxiway Quebec at Amsterdam Airport Schiphol in the Netherlands with Lufthansa Regional / Lufthanse CityLine.